Module pulse 

Pulse — a wrapper widget that pulses its child’s opacity between a min and max value on a fixed period, sine-shaped.

The classic “blinking red light” / recording-indicator / attention beacon pattern. The wrapped subtree pulses smoothly (sine interpolation), giving a breathing-light feel rather than a hard on/off blink.

ctx.add(
    Pulse::opacity(0.3, 1.0)
        .period(Duration::from_millis(1200))
        .child(RectWidget::new().background(Color::RED)),
);

Layout semantics

Layout-transparent — the child reports its full natural size at all opacity values. Identical layout footprint to Fade.

Reduced motion

Honours prefers-reduced-motion: skips the per-frame driver and pins opacity at the midpoint (min + max) / 2. The subtree stays visible at a steady, non-distracting brightness so the indicator still communicates “active” without animating.

Structs

Pulse

Wraps a child and pulses its opacity smoothly between min and max on a fixed period. Useful for recording indicators, notification beacons, and attention-grabbing status icons.